RFR: 8353263: Parallel: Remove locking in PSOldGen::resize

[Albert Mingkun Yang]

Simple removing the use of `PSOldGenExpand_lock` in resizing logic after full-gc, because the calling context is inside a safepoint.

Test: tier1-5

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Commit messages:
 - pgc-remove-resize-lock

Changes: https://git.openjdk.org/jdk/pull/24322/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24322&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353263
  Stats: 5 lines in 1 file changed: 1 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/24322.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24322/head:pull/24322

PR: https://git.openjdk.org/jdk/pull/24322